Re: [PATCH V2] Add flag to start info regarding virtual mapped p2m list

[David Vrabel <david.vrabel@citrix.com>]

On 04/03/15 11:09, Juergen Gross wrote:
> On 03/04/2015 11:59 AM, David Vrabel wrote:
>> On 04/03/15 10:20, Juergen Gross wrote:
>>>
>>> I could, of course, wait with the flag bit until xl is ready and post
>>> another kernel patch then. Unfortunately this would delay Linux support
>>> for automatically be able to run as a pv-domain >500GB further, so I
>>> strongly recommend accepting the interface change now.
>>
>> I suggested before:
>>
>> "If dom0, enable >512G.
>> If domU, enable >512G if requested by command line option /or/ toolstack
>> indicates that it supports the linear p2m."
>>
>> So this flag is only required to /automatically/ enable >512GB PV
>> guests.  You still need the manual (command line) override so this flag
>> isn't needed until the toolstack actually supports the linear p2m, and
>> the kernel support for this automatic enablement can be added later as
>> well.
> 
> Correct. The question is, whether we want some kernel versions capable
> of running as 1TB guest requiring an additional boot parameter to do so.
> Avoiding this is easy, but if you don't like it, I can wait with this
> patch.

I think running such large PV domUs is a sufficiently rare use case that
this is fine.

David